Piece with very well-preserved details.
Obverse: crowned eagle of the Russian Empire, on the sides of the tail the initials of the mincmaster, in the rim the legend:
ЧИСТAГО СЕРЕБРА 4 ЗОЛОТНИКА 21 ДОЛЯ;
Reverse: in laurel and oak wreath crowned inscription:
МОНЕТА/РУБЛЬ/1851/ С.П.Б.;